Question

Click in the answer box to activate the palette. List the following molecules in order of increasing dipole moment: H2O, CBr4, H2S, HF, NH3, CO2 < < < < Electronegativities H 2.1 C 2.5 N 3.0 O 3.5 F 4.0 S 2.5 Br 2.8

Answer 1

Answer:

HF > H2O > NH3 > H2S > CBr4=CO2=0

Explanation:

Dipole moment is a vector quantity. Its a measure of polarity of a bond in a molecule and also a meaure of separation of positive and negative charge in a system.It occurs due to electronegativity difference between the atoms in a molecule.

In order for a molecule to have dipole moment, a molecule must exhibit high electronegativity difference and the shape of the moloecule must be asymmetry

HF has the highest electronegativity difference among all the molecules listed above hence its dipole moment is the greatest.

$H_{2}O$ has a bent structure. There are two O-H bonds hence more charge dipoles. The dipole moment is less than HF molecule because of the net dipole moments of two O-H bonds.

$CO_{2}$ is a linear molecule.However it has polar bonds.But because of the shape of the molecule, the two C-O bond dipoles cancel out each other hence the overall dipole moment will be zero.

Similarly in $CBr_{4}$, ,since the molecule is symmetry, the bond dipole cancels each other out hence the overall dipole moment will be zero.